1. Field of the Invention
This invention relates to dynamic adaptation of link parameters for wireless communication; in particular, the invention relates to dynamic adaptation of link parameters such as modulation scheme, symbol rate, and error correction scheme for a wireless communication link.
2. Description of the Related Art
Conventional wireless communication systems adapt their modulation schemes based on periodic measurements of channel quality. A measurement of channel quality used by these systems is a bit error rate (BER) statistic. These conventional systems have several drawbacks.
First, different modulation schemes can have radically different throughput efficiencies and error tolerances. As a result, a change in modulation schemes to accommodate an increase in communication errors can result in an unacceptable decrease in throughput efficiency.
Second, BER statistics take some time to change in order to reflect an increase in communication errors. The periodic nature of BER statistic computations exacerbates this problem. In particular, a change in a rate of communication errors is not reflected in the BER statistics until an end of a period. If the error rate changes near the end of the period, the BER statistics may not reflect the change until the end of the next period. During this delay, a modulation scheme with unacceptable error tolerance may be utilized, adversely impacting communication over a wireless link.